Si含量对激光选区熔化Hastelloy X合金组织及持久性能的影响  

Influence of Si Content on Microstructures and Stress Rupture Properties of Hastelloy X Alloy Formed by Selective Laser Melting

作　　者：李雅莉 何艳丽 付俊 张剑锋 Li Yali;He Yanli;Fu Jun;Zhang Jianfeng(Materials Engineering Department,AECC Commercial Aircraft EngineCo.,Ltd.,Shanghai 201306,China)

机构地区：[1]中国航发商用航空发动机有限责任公司材料工程部,上海201306

出　　处：《中国激光》2024年第20期225-232,共8页Chinese Journal of Lasers

基　　金：青年人才托举工程项目(YESS20220738AE);国家自然科学基金(52105163);上海市科技启明星项目(22QB1406400)。

摘　　要：研究了A(Si的质量分数为0.071%)、B(Si的质量分数为0.365%)两批次Hastelloy X合金激光选区熔化试样的显微组织及持久性能。结果表明:在815℃/105 MPa持久试验前,A批次试样的碳化物在晶界及晶内均有发现,晶界析出物呈链状分布,碳化物类型为富含Cr元素的M_(23)C_(6)型碳化物,B批次试样的碳化物主要在晶界处较连续析出,碳化物类型为富含Mo元素的M6C型碳化物;在持久试验后,A批次试样的析出物无明显变化,B批次试样的晶内产生了较多针状析出相MoSiW。此外,A批次试样的持久性能均达到锻件标准,而B批次试样持久性能中的塑性较低,平均延伸率为6.4%,低于锻件标准。Hastelloy X合金析出相的形态、分布及类型等与Si含量密切相关,当Si元素质量分数(0.365%)较高时,在持久试验过程中,晶内密集析出针状硬脆相,晶界碳化物近乎连成一体,影响晶界之间的结合力,降低合金的持久性能。Objective Hastelloy X alloy is commonly used to manufacture high-temperature components such as the combustion chambers of aero-engines by selective laser melting(SLM).In practice,even when using the same SLM process,heat treatment,and hot isostatic pressing process,there are differences in the microstructures and mechanical properties of different batches of Hastelloy X alloy parts.There is a strong correlation among these differences and differences in the compositions of the batches of Hastelloy X alloy powder raw material used.In particular,the influence of the Si element is the most significant.The existing research mainly focuses on the use of the Si element in the traditional casting or forging process for the preparation of nickel-based high temperature alloys,with little attention given to the Si element in the Hastelloy X alloy in SLM-related research.This study discusses the effect of Si on the microstructure and stress rupture properties of SLM formed Hastelloy X alloy parts,with a view to providing useful guidance for optimizing their quality.Methods Two batches of gas-aerosolized Hastelloy X powders with different Si compositions,A(Si mass fraction of 0.071%)and B(Si mass fraction of 0.365%),are used in this experiment,with particle sizes ranging from 15μm to 45μm.The experiment is carried out using the SLM equipment.The SLM forming parameters of the two batches are the same,and the specimens are placed in the length direction parallel to the substrate(transverse specimens).After the SLM is finished,each sample is subjected to hot treatment at 1050℃for 1 h to remove the thermal stress,and then hot isostatic pressing at 1150℃for 2 h is performed.A scanning electron microscope(SEM)is used to observe the high magnification microstructure of the Hastelloy X alloy,and the compositions of the phases at the grain boundaries are analyzed using an SEM energy dispersive spectrometer(SEM-EDS).The type of needle-like precipitates is analyzed using a transmission electron microscope(TEM).The stress rupture

关 键 词：激光选区熔化 Hastelloy X SI含量 显微组织 持久性能 

分 类 号：TG456.7[金属学及工艺—焊接]